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At least 253 records · Page 14Linked to original sources
USGS2015

Dreissenid mussel research priorities workshop

Currently, dreissenid mussels have yet to be detected in the northwestern part of the United States and western Canada. Infestation of one of the jurisdictions within the mussel-free Pacific Northwest would likely have significant economic, soci­etal and environmental implications for the entire region. Understanding the biology and environmental tolerances of dreissenid mussels, and effectiveness of various man­agement strategies, is key to prevention. On November 4-5, 2015, the Aquatic Bioinvasion Research and Policy Institute and the Center for Lakes and Reservoirs at Portland State University, the US Geological Survey, and the Pacific States Marine Fisheries Commission, convened a Dreissenid Mussel Research Priorities Workshop funded by the Great Northern Landscape Conservation Cooperative. The purpose of the workshop was to review dreissenid research priorities in the 2010 Quagga-Zebra Mussel Action Plan for Western U.S. Waters, reassess those priorities, incorporate new information and emerging trends, and develop priorities to strategically focus research efforts on zebra and quagga mussels in the Pacific Northwest and ensure that future research is focused on the highest priorities. It is important to note that there is some repetition among dreissenid research priority categories (e.g., prevention, detection, control, monitoring, and biology). Workshop participants with research experience in dreissenid mussel biology and management were identified by a literature review. State and federal agency managers were also invited to the workshop to ensure relevancy and practicality of the work­shop outcomes. A total of 28 experts (see sidebar) in mussel biology, ecology, and management attended the workshop.

Conference Paper↗
USGS2025

Wet meadow regeneration through restoration of biophysical feedbacks

Wet meadows are globally significant ecosystems that provide critical hydrological, ecological, and biogeochemical functions, yet their extent has declined dramatically due to land use changes and hydrologic alteration. These sedge-dominated wetlands exist at the drier end of the wetland gradient, maintained by shallow groundwater and periodic inundation. This paper is a global synthesis of the ecological, geomorphic, and hydrological dynamics of wet meadows, with an emphasis on alluvial systems, to inform effective restoration strategies. We compare wet meadows to other wetlands, classify them into palustrine, lacustrine, and alluvial types, then focus on alluvial wet meadows and discuss how their formation and persistence depend on ground and surface water interactions, sediment deposition and flow obstructions, all mediated by biological processes. In particular, we highlight the role of hydric graminoids in resisting erosion and maintaining soil cohesion, how beaver promote meadow persistence, and the significance of wet meadows as carbon sinks. We also present stratigraphic evidence demonstrating that incision, often triggered by anthropogenic activity or changing climate, is the primary mechanism of alluvial wet meadow degradation, resulting in water table decline and shifts in vegetation composition. Restoration requires reversing these incisional processes through techniques that elevate water tables, disperse flow and retain sediment—methods traditionally associated with either soil conservation or stream restoration. These include nature-based solutions that create obstructions such as beaver dams and their analogues, rock and wood-based obstructions and incision trench or gully filling and grading. Given their multifunctional value—including but not limited to flood attenuation, biodiversity support, and carbon sequestration—wet meadows warrant a focused restoration framework. This review advocates for a valley-floor scale restoration paradigm that integrates hydrological reconnection, sediment retention, and biological reinforcement to ensure long-term resilience of these systems in the face of changing climate and land use pressures.

Frontiers in Environmental Science↗
USGS2006

The diamondback terrapin: The biology, ecology, cultural history, and conservation status of an obligate estuarine turtle

Ranging from Cape Cod to nearly the Texas-Mexico border, the diamondback terrapin (Malaclemys terrapin) is the only species of North American turtle restricted to estuarine systems. Despite this extensive distribution, its zone of occurrence is very linear, and in places fragmented, resulting in a relatively small total area of occupancy. On a global scale, excluding marine species, few turtles even venture into brackish water on a regular basis, and only two Asian species approach the North American terrapin's dependency on estuarine habitats. Here we describe some of the biological and behavioral adaptations of terrapins that allow them to live in the rather harsh estuarine environment. In this chapter we review the natural and cultural history of this turtle, discuss conservation issues, and provide information on the types of research needed to make sound management decisions for terrapin populations in peril.

Studies in Avian Biology↗
USGS2015

Nest predation research: Recent findings and future perspectives

Nest predation is a key source of selection for birds that has attracted increasing attention from ornithologists. The inclusion of new concepts applicable to nest predation that stem from social information, eavesdropping or physiology has expanded our knowledge considerably. Recent methodological advancements now allow focus on all three players within nest predation interactions: adults, offspring and predators. Indeed, the study of nest predation now forms a vital part of avian research in several fields, including animal behaviour, population ecology, evolution and conservation biology. However, within nest predation research there are important aspects that require further development, such as the comparison between ecological and evolutionary antipredator responses, and the role of anthropogenic change. We hope this review of recent findings and the presentation of new research avenues will encourage researchers to study this important and interesting selective pressure, and ultimately will help us to better understand the biology of birds.

Journal of Ornithology↗
USGS2019

From theory to experiments for testing the proximate mechanisms of mast seeding: An agenda for an experimental ecology

Highly variable and synchronised production of seeds by plant populations is called masting and is implicated in many important ecological processes, but how it arises remains poorly understood. The lack of experimental studies prevents underlying mechanisms from being explicitly tested, and thereby precludes meaningful predictions on the consequences of changing environments for plant reproductive patterns and global vegetation dynamics. Here we review the most relevant hypothetical drivers of masting and outline a research agenda that takes the biology of masting from a largely observational field of ecology to one rooted in mechanistic understanding. We divide the experimental framework into three main processes: resource dynamics, pollen limitation, and genetic and hormonal regulation, and illustrate how specific predictions about proximate mechanisms can be tested, highlighting the few successful experiments as examples. We envision that the experiments we outline will deliver new insights into how and why masting patterns might respond to a changing environment.

Ecology Letters↗
USGS1999

Assessing biological effects from highway-runoff constituents

Increased emphasis on evaluation of nonpoint-source pollution has intensified the need for techniques that can be used to discern the toxicological effects of complex chemical mixtures. In response, the use of biological assessment techniques is receiving increased regulatory emphasis. When applied with documented habitat assessment and chemical analysis, these techniques can increase our understanding of the influence of environmental contaminants on the biological integrity and ecological function of aquatic communities. The contaminants of greatest potential concern in highway runoff are those that arise from highway construction, maintenance, and use. The major contaminants of interest are deicers; nutrients; metals; petroleum-related organic compounds, such as polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, ethylbenzene, and xylene (BTEX), and methyl tert -butyl ether (MTBE); sediment washed off the road surface; and agricultural chemicals used in highway maintenance. Hundreds, if not thousands, of biological endpoints (measurable responses of living organisms) may be either directly or associatively affected by contaminant exposure. Measurable effects can occur throughout ecosystem processes across the wide range of biological complexity, ranging from responses at the biochemical level to the community level. The challenge to the environmental scientist is to develop an understanding of the relationship of effects at various levels of biological organization in order to determine whether a causal relationship exists between chemical exposure and substantial ecological impairment. This report provides a brief history of the evolution of biological assessment techniques, a description of the major classes of contaminants that are of particular interest in highway runoff, an overview of representative biological assessment techniques, and a discussion of data-quality considerations. Published reports with a focus on the effects of highway runoff on the local ecosystem were reviewed to provide information on (1) the suitability of the existing data for a quantitative national synthesis, (2) the methods available to study the effects of highway runoff on local ecosystems, and (3) the potential for adverse effects on the roadside environment and receiving waters. Although many biological studies have been done, the use of different methods and a general lack of sufficient documentation precludes a quantitative national synthesis on the basis of the existing data. The Federal Highway Administration, the U.S. Environmental Protection Agency, the U.S. Geological Survey, the Intergovernmental Task Force on Monitoring Water Quality, and the National Resources Conservation Service all have developed and documented methods for assessing the effects of contaminants on ecosystems in receiving waters. These published methods can be used to formulate a set of protocols to provide consistent information from highway-runoff studies. Review of the literature indicates (qualitatively) that highway runoff (even from highways with high traffic volume) may not usually be acutely toxic. Tissue analysis and community assessments, however, indicate effects from highway- runoff sediments near discharge points (even from sites near highways with relatively low traffic volumes). At many sites, elevated concentrations of highway-runoff constituents were measured in tissues of species associated with aquatic sediments. Community assessments also indicate decreases in the diversity and productivity of aquatic ecosystems at some sites receiving highway runoff. These results are not definitive, however, and depend on many site-specific criteria that were not sufficiently documented in most of the studies reviewed.

Open-File Report↗
USGS1992

Diflubenzuron Hazards to Fish, Wildlife and Invertebrates: A Synoptic Review

Diflubenzuron (1(4chlorophenyl)3(2,6difluorobenzoyl)urea), also known as dimilin, is a potent broad spectrum insect growth regulator that interferes with chitin synthesis at time of molting and is effective in controlling immature stages of insects. Diflubenzuron was approved for domestic use in 1976 to control gypsy moth (Lymantria dispar), and in 1979 against the cotton boll weevil (Anthonomus grandis). By 1989 this compound was also registered for domestic use against mosquitos, forest Lepidoptera, mushroom flies, and leaf-eating insect pests of citrus, woody ornamentals, vegetables, and fruit. Diflubenzuron seldom persists for more than a few days in soil and water. When used properly in forest management, it is unlikely to be leached into ground water from the application site. Degradation in water and soil is most rapid when small particle formulations are applied; microorganisms are abundant; and at elevated pH, temperature, and organic loading. Chemical and biological processes initially yield 2,6difluorobenzoic acid and 4chlorophenylurea.

Contaminant Hazard Reviews↗
USGS2018

Critical review: Grand challenges in assessing the adverse effects of contaminants of emerging concern on aquatic food webs

Much progress has been made in the past few decades in understanding the sources, transport, fate, and biological effects of contaminants of emerging concern (CECs) in aquatic ecosystems. Despite these advancements, significant obstacles still prevent comprehensive assessments of the environmental risks associated with the presence of CECs. Many of these obstacles center around the extrapolation of effects of single chemicals observed in the laboratory or effects found in individual organisms or species in the field to impacts of multiple stressors on aquatic food webs. In the present review, we identify 5 challenges that must be addressed to promote studies of CECs from singular exposure events to multispecies aquatic food web interactions. There needs to be: 1) more detailed information on the complexity of mixtures of CECs in the aquatic environment, 2) a greater understanding of the sublethal effects of CECs on a wide range of aquatic organisms, 3) an ascertaining of the biological consequences of variable duration CEC exposures within and across generations in aquatic species, 4) a linkage of multiple stressors with CEC exposure in aquatic systems, and 5) a documenting of the trophic consequences of CEC exposure across aquatic food webs. We examine the current literature to show how these challenges can be addressed to fill knowledge gaps.

Environmental Toxicology and Chemistry↗
USGS2020

Acidification in the U.S. Southeast: Causes, potential consequences and the role of the Southeast Ocean and Coastal Acidification Network

Coastal acidification in southeastern U.S. estuaries and coastal waters is influenced by biological activity, run-off from the land, and increasing carbon dioxide in the atmosphere. Acidification can negatively impact coastal resources such as shellfish, finfish, and coral reefs, and the communities that rely on them. Organismal responses for species located in the U.S. Southeast document large negative impacts of acidification, especially in larval stages. For example, the toxicity of pesticides increases under acidified conditions and the combination of acidification and low oxygen has profoundly negative influences on genes regulating oxygen consumption. In corals, the rate of calcification decreases with acidification and processes such as wound recovery, reproduction, and recruitment are negatively impacted. Minimizing the changes in global ocean chemistry will ultimately depend on the reduction of carbon dioxide emissions, but adaptation to these changes and mitigation of the local stressors that exacerbate global acidification can be addressed locally. The evolution of our knowledge of acidification, from basic understanding of the problem to the emergence of applied research and monitoring, has been facilitated by the development of regional Coastal Acidification Networks (CANs) across the United States. This synthesis is a product of the Southeast Coastal and Ocean Acidification Network (SOCAN). SOCAN was established to better understand acidification in the coastal waters of the U.S. Southeast and to foster communication among scientists, resource managers, businesses, and governments in the region. Here we review acidification issues in the U.S. Southeast, including the regional mechanisms of acidification and their potential impacts on biological resources and coastal communities. We recommend research and monitoring priorities and discuss the role SOCAN has in advancing acidification research and mitigation of and adaptation to these changes.

Florida, Georgia, North Carolina, South Carolina↗
USGS2003

Climate variability and change in high elevation regions: Past, present & future

This special issue of Climatic Change contains a series of research and review articles, arising from papers that were presented and discussed at a workshop held in Davos, Switzerland on 25–28 June 2001. The workshop was titled ‘Climate Change at High Elevation Sites: Emerging Impacts’, and was convened to reprise an earlier conference on the same subject that was held in Wengen, Switzerland in 1995 (Diaz et al., 1997). The Davos meeting had as its main goals, a discussion of the following key issues: (1) reviewing recent climatic trends in high elevation regions of the world, (2) assessing the reliability of various biological indicators as indicators of climatic change, and (3) assessing whether physical impacts of climatic change in high elevation areas are becoming evident, and to discuss a range of monitoring strategies needed to observe and to understand the nature of any changes.

Climatic Change↗
USGS2002

Ecological effects on streams from forest fertilization: Literature review and conceptual framework for future study in the western Cascades

Fertilization of forests with urea-nitrogen has been studied numerous times for its effects on water quality. Stream nitrogen concentrations following fertilization are typically elevated during winter, including peaks in the tens-of-thousands of parts per billion range, with summer concentrations often returning to background or near-background levels. Despite these increases, water-quality criteria for nitrogen have rarely been exceeded. However, such criteria are targeted at fish toxicity or human health and are not relevant to concentrations that could cause ecological disturbances. Studies of the responses of stream biota to fertilization have been rare and have targeted either immediate, toxicity-based responses or used methods insensitive to ongoing ecological processes. This report reviews water-quality studies following forest fertilizations, emphasizing Cascade streams in the Pacific Northwest and documented biological responses in those streams. A conceptual model predicting potential ecological response to fertilization, which includes effects on algal growth and primary production, is presented. In this model, applied fertilizer nitrogen reaching streams is mostly exported during winter. However, some nitrogen retained in soils or stream and riparian areas may become available to aquatic biota during spring and summer. Biological responses may be minimal in small streams nearest to application because of light limitation, but may be elevated downstream where light is sufficient to allow algal growth. Ultimately, algal response could be greatest in downstream reaches, although ambient nutrient concentrations remain low due to uptake and benthic nutrient recycling. Ground-water flow paths and hyporheic processing could be critical in determining the fate of applied nitrogen. A framework is provided for testing this response in the Little River watershed, a tributary to the North Umpqua River, Oregon, at basic and intensive levels of investigation.

Oregon↗
USGS2017

A synthesis of thresholds for focal species along the U.S. Atlantic and Gulf Coasts: A review of research and applications

The impacts from climate change are increasing the possibility of vulnerable coastal species and habitats crossing critical thresholds that could spur rapid and possibly irreversible changes. For species of high conservation concern, improved knowledge of quantitative thresholds could greatly improve management. To meet this need, we synthesized information pertaining to biological responses as tipping points to sea level rise (SLR) and coastal storms for 45 fish, wildlife, and plant species along the U.S. Atlantic and Gulf Coasts and Caribbean through a literature review and expert elicitation. Although these species were selected based on their ecological, economic, and cultural importance, just over half (56%, n = 25) have quantitative threshold data currently available that can be used to assess the effects of SLR and storms during some aspect of their life history. Birds, reptiles, and plants represent the best studied coastal species. Thirteen of the species (29%) are projected to lose at least 50% of their population or habitat (e.g., foraging, nesting, spawning, or resting habitat) in some areas with a 0.5 m or greater rise in sea levels by 2100. Two species (a bird and reptile) may gain habitat from projected SLR and be resilient to future impacts. Numeric thresholds were not available for the remaining 20 species we searched for. Coastal fishes, mammals, and amphibians were among the groups representing a major information gap in this field of research. In addition, quantitative threshold responses to coastal storms were scarce for all taxa. While vulnerability assessments and qualitative research related to the impacts of SLR and storms on coastal species and habitats are increasing, work that incorporates quantitative thresholds as response and impact metrics remains limited. Additional monitoring, modeling, and research that provides multiple quantitative thresholds across species' life stages and/or latitudinal gradients is ideal to support robust coastal management and decision-making across spatio-temporal scales in the face of climate change.

Ocean and Coastal Management↗
USGS2001

Green fluorescent protein is lighting up fungal biology

Prasher ( 42 ) cloned a cDNA for the green fluorescent protein (GFP) gene from the jellyfish Aequorea victoria in 1992. Shortly thereafter, to the amazement of many investigators, this gene or derivatives thereof were successfully expressed and conferred fluorescence to bacteria and Caenorhabditis elegans cells in culture ( 10 , 31 ), followed by yeast ( 24 , 39 ), mammals ( 40 ), Drosophila ( 66 ), Dictyostelium ( 23 , 30 ), plants ( 28 , 49 ), and filamentous fungi ( 54 ). The tremendous success of GFP as a reporter can be attributed to unique qualities of this 238-amino-acid, 27-kDa protein which absorbs light at maxima of 395 and 475 nm and emits light at a maximum of 508 nm. The fluorescence of GFP requires only UV or blue light and oxygen, and therefore, unlike the case with other reporters (β-glucuronidase, β-galacturonidase, chloramphenicol acetyltransferase, and firefly luciferase) that rely on cofactors or substrates for activity, in vivo observation of gfp expression is possible with individual cells, with cell populations, or in whole organisms interacting with symbionts or environments in real time. Complications caused by destructive sampling, cell permeablization for substrates, or leakage of products do not occur. Furthermore, the GFP protein is extremely stable in vivo and has been fused to the C or N terminus of many cellular and extracellular proteins without a loss of activity, thereby permitting the tagging of proteins for gene regulation analysis, protein localization, or specific organelle labeling. The mature protein resists many proteases and is stable up to 65°C and at pH 5 to 11, in 1% sodium dodecyl sulfate or 6 M guanidinium chloride (reviewed in references 17 and 67 ), and in tissue fixed with formaldehyde, methanol, or glutaraldehyde. However, GFP loses fluorescence in methanol-acetic acid (3:1) and can be masked by autofluorescent aldehyde groups in tissue fixed with glutaraldehyde. Fluorescence is optimal at pH 7.2 to 8.0 ( 67 ). Limitations on GFP as a reporter for some applications are its low turnover rate, 2-h lag time for autoactivation of its chromophore, improper folding at high temperatures (37°C), which results in nonfluorescent and insoluble forms of the protein, and requirement for oxygen, which is not present in equal concentrations in all subcellular locations or cell types (reviewed in references 17 and 67 ). These characteristics of GFP, however, have not posed a problem for many applications, and mutant forms of GFP that have an ability to fold properly at high temperatures, increased solubility and fluorescence, reduced photobleaching ( 16 , 17 , 51 ), and reduced half-lives ( 1 ) have been developed. Coupled with fluorescence-activated cell sorting, confocal microscopy or quantitative image analysis techniques, GFP technology can be used to isolate transformed cells or specific cell types from populations of cells ( 14 ), to quantify gene expression of individual cells within whole organisms ( 8 ), or to assess the dispersal and biomass of organisms in complex environments, such as in animal or plant hosts ( 38 , 59 ), in biofilms ( 55 ), in fermentors ( 41 ), on leaf surfaces ( 53 , 61 ), or in soils ( 2 ). The vast majority of studies utilizing GFP expression in fungi have been with yeast (reviewed in reference 13 ). Ustilago maydis was the first filamentous fungus for which successful expression of gfp was reported ( 54 ), followed closely by Aspergillus nidulans ( 22 , 57 ) and Aureobasidium pullulans ( 61 ). Presently, gfp expression has been reported for 16 species comprising 12 genera of filamentous fungi, including Colletotrichum ( 21 , 44 ), Mycosphaerella ( 52 ), Magnaporthe ( 32 , 35 ), Cochliobolus ( 38 ), Trichoderma ( 2 , 70 ), Podospora ( 5 ), Sclerotinia ( 63 ), Schizophyllum ( 37 ), Aspergillus ( 20 , 47 , 50 ) and Phytophthora ( 7 , 62 ). In this review we draw on published reports, with the goal of providing an overview of GFP technology as it applies to the biology of filamentous fungi. These reports are not exhaustive of potential applications of GFP technology, as examples of genomic approaches to utilizing GFP in bacterial and yeast systems attest ( 4 , 46 , 60 , 65 ). Expression of gfp in filamentous fungi requires a gfp variant that is efficiently translated in fungi, a transformation system, and a fungal promoter that satisfies the requirements of a given experimental objective. Transformation of fungi has recently been reviewed by Gold et al. ( 26 ). Robinson and Sharon ( 44 ) suggest that GFP can actually be used to optimize transformation protocols. In addition to reporting the construction of a new fungal transformation vector that expresses SGFP under the control of the ToxA gene promoter from Pyrenophora tritici-repentis ( 12 ) and demonstrating its use in plant pathogens belonging to eight different genera of filamentous fungi ( Fusarium, Botrytis, Pyrenophora, Alternaria, Cochliobolus, Sclerotinia, Colletotrichum , and Verticillium ), in this review we also enumerate and describe a comprehensive list of vectors for expressing GFP in fungi.

Applied and Environmental Microbiology↗
USGS2015

The scaling of geographic ranges: implications for species distribution models

Context The geographic ranges of many species are responding to ongoing environmental change. Processes operating at different levels of biological organization, with corresponding spatial extents and grains and temporal rates, interact with the evolving configuration of environmental conditions to determine range dynamics. Objectives To synthesize understanding of scales and scaling, including relevant biological levels of organization, focusing on the processes that mediate species-environment relationships and the models used to make inferences about species distributions. Methods We review concepts related to the scaling of geographic ranges and implications for the most commonly used analytic methods, using simple simulations to illustrate important issues. Results Many processes lead to species distributions being dependent on environmental conditions within sites and within a neighborhood. Studies with large extents and fine grains can cut across several levels of biological organization (individual, within-population, and metapopulation processes) complicating interpretation. Many geographic ranges are not in dynamic equilibrium, but common models used for inference assume equilibrium. Interspecific interactions shape species distributions at multiple scales, and arguments for ignoring species interactions also assume equilibrium. Conclusions There is a need for timely science to inform policy and management decisions; however, we must also strive to provide predictions that best reflect our understanding of ecological systems. Species distributions evolve through time and reflect responses to environmental conditions that are mediated through individual and population processes. Species distribution models that reflect this understanding, and explicitly model dynamics, are likely to give more accurate predictions.

Landscape Ecology↗
USGS2014

Non-native fishes in Florida freshwaters: a literature review and synthesis

Non-native fishes have been known from freshwater ecosystems of Florida since the 1950s, and dozens of species have established self-sustaining populations. Nonetheless, no synthesis of data collected on those species in Florida has been published until now. We searched the literature for peer-reviewed publications reporting original data for 42 species of non-native fishes in Florida that are currently established, were established in the past, or are sustained by human intervention. Since the 1950s, the number of non-native fish species increased steadily at a rate of roughly six new species per decade. Studies documented (in decreasing abundance): geographic location/range expansion, life- and natural-history characteristics (e.g., diet, habitat use), ecophysiology, community composition, population structure, behaviour, aquatic-plant management, and fisheries/aquaculture. Although there is a great deal of taxonomic uncertainty and confusion associated with many taxa, very few studies focused on clarifying taxonomic ambiguities of non-native fishes in the State. Most studies were descriptive; only 15 % were manipulative. Risk assessments, population-control studies and evaluations of effects of non-native fishes were rare topics for research, although they are highly valued by natural-resource managers. Though some authors equated lack of data with lack of effects, research is needed to confirm or deny conclusions. Much more is known regarding the effects of lionfish ( Pterois spp.) on native fauna, despite its much shorter establishment time. Natural-resource managers need biological and ecological information to make policy decisions regarding non-native fishes. Given the near-absence of empirical data on effects of Florida non-native fishes, and the lengthy time-frames usually needed to collect such information, we provide suggestions for data collection in a manner that may be useful in the evaluation and prediction of non-native fish effects.

Florida↗
USGS2020

Book review: Proceedings of the First International Snakehead Symposium

Snakehead fishes (family Channidae) are among the most maligned aquatic invasive species in the USA and some other countries where they have been introduced outside of their native range in Asia and Africa. Nevertheless, snakeheads continue to be widely exploited in the live‐food trade in aquaculture and wild‐capture fisheries, are highly sought by anglers, and are also popular in the aquarium trade (Courtenay and Williams 2004). The Northern Snakehead Channa argus is the most widespread of the three channid species that are currently naturalized in the USA. This species has generated much concern and controversy, a situation that is partly fueled by sensational media coverage and B‐grade science fiction horror films, such as “Frankenfish,” “Snakehead Terror,” and “Snakehead Swamp.” Media reports of snakehead introductions are often replete with provocative terms, such as “vicious,” “villain,” “voracious,” “monster,” “diabolical,” and even “ecological Armageddon.” When snakeheads first appeared in natural waters of the USA, fisheries professionals became increasingly interested in their status. Established populations rapidly expanded in the mid‐Atlantic region and Arkansas, with scattered reports of introduced snakeheads from isolated locations in Hawaii, California, North Carolina, Florida, the Upper Midwest, and New England. In 2002, snakeheads were added to the list of injurious fishes under the Lacey Act, thereby prohibiting their importation or transport across state lines without a permit. This symposium was conceived by the editors and other concerned fisheries professionals of the Mississippi River Basin Panel on Aquatic Invasive Species. The mission of the symposium, held in Alexandria, Virginia, in July 2018, was to bring together experts on snakehead biology and ecology and to synthesize existing information into summary papers. In this book, 35 authors contributed to 15 peer‐reviewed articles that detail the current state of knowledge about snakehead introductions in the USA. Additionally, 16 abstracts are included from meeting presentations that were not accompanied by full‐length manuscripts. Also included is a summary of a facilitated symposium panel discussion featuring eight experts representing state and federal natural resource agencies and private fishing organizations. The book is organized into six sections. In the first section (Distribution), three papers provide an overview of the Channa species introduced into the USA and historical accounts of occurrence and dispersal of the Northern Snakehead in the mid‐Atlantic region and Arkansas. The second section (Biology/Ecology) consists of two articles that examine growth and energetics of Northern Snakehead populations and two papers that investigate diet, diel feeding activity, and movement of this species in the Potomac River drainage. The third section (Monitoring/Response) includes a paper that models range expansion of the Northern Snakehead in the southeastern USA based on occurrence data and environmental conditions. Also included in this section is a paper summarizing an environmental DNA study to assess the status and range of the Bullseye Snakehead C. marulius in southern Florida. The fourth section (Management/Control) is comprised of four papers that address harvest, age and growth, and development of a stock–recruitment model to inform management decisions regarding control and mitigation for Northern Snakehead populations in the greater Chesapeake Bay area. The fifth section (Perspectives) includes a paper on the history of snakehead introductions in Japan and a thought‐provoking social commentary on the human dimensions of Northern Snakehead management. Abstracts in the final section provide brief summaries of a diversity of snakehead studies, including aspects of distribution, ecology, behavior, control and monitoring efforts, public outreach, and pathology. The summary of the panel discussion is an engaging dialogue about the challenges of snakehead management in the context of conflicts regarding snakeheads as injurious versus their value as game and food species. Most of this book is focused on the Northern Snakehead. Much has been done to document snakehead distributions and certain aspects of snakehead biology, such as diets, age, and growth. Less research has been devoted to understanding the ecological impacts of snakeheads to native aquatic communities and ecosystems. This book would have benefited from a chapter summarizing the current systematics and diversity of the Channidae to inform fisheries biologists about the morphological characteristics of the family, approximate numbers of genera and species, and taxonomic instability. Exemplifying the latter, recent molecular and morphological evidence indicates uncertainty regarding identification of the feral snakehead population in Florida (Adamson and Britz 2019). Those authors suggest that this population may have originated from western Thailand, a possibility that could have implications for understanding historical pathways of snakehead introductions into the USA. In comparison with many published AFS symposia, this volume is relatively narrow in scope and lacks cohesive integration. It will primarily be of interest to those fisheries professionals engaged in the study of snakeheads as well as other nonnative species for which there are contrasting social values regarding their management: whether to monitor and attempt control or eradication efforts or to maintain populations for harvest as game or food species. The book should serve to identify information gaps and guide future research.

Transactions of the American Fisheries Society↗